Short-term memory

The rule of seven

(Miller, 1959)
Things you are consciously thinking about are held in short-term memory, which has a limited capacity. Most people can hold only 7 pieces of information in short-term memory at any time. Some people can hold 9 pieces, and some only 5, but the average is 7.

Most of us can look at a 7-digit phone number and remember it long enough to dial it. However, we have trouble with the new 8-digit numbers. Of course, we know the new number, the first number is always 9, but that is an extra piece of information. There isn’t room to store 7 digits plus the information that the eight digit is a 9.

Chunking

(Miller again)
You can effectively expand the capacity of short-term memory by using meaningful pieces, or chunks of information. Can you remember the names and order of the nine planets in the Solar system?

A silly mnemonic takes up only one chunk. The rule for decoding it takes up another chunk!

This brings us to the idea of Long-term memory and Associations.

Some implications of the Computer Model of short-term memory

• Write lists. It isn’t fair to give someone a string of 7 verbal instructions and expect them carried out. As soon as they start thinking about pen and paper, they’ll forget at least 1 instruction.
• Don’t interrupt people who are concentrating. To listen to you, they have to forget part of what they are thinking about.
• Use pen and paper to work out complicated problems. If you do it in your head you are likely to forget things, then forget you forgot them.
• You WON’T remember it later, except with luck!
• The cheapest memory upgrade is a notebook!
• Don’t try to learn too much at once. Your memory will overflow and you’ll lose information!

Notes for trainers

Beware of cognitively overloading the learners:

Use a familiar idea in an unfamiliar situation, or an unfamiliar idea in a familiar situation, but don’t introduce new ideas and situations simultaneously.

Introduce new ideas using familiar words. Once they have grasped the new ideas introduce the new language.

Draw their attention to the important points by:

• changing the pitch, intensity or inflection of your voice
• using colour or formatting in text
• using animation, movement, sound or lighting effects
• any means necessary!